Virus Not Culprit in Pulmonary Fibrosis Flares

The cause of exacerbations of a progressive and uniformly fatal lung disease remains a mystery.

But in most cases, acute worsening of idiopathic pulmonary fibrosis does not appear to result from a viral infection, according to Harold Collard, MD, of the University of California San Francisco, and colleagues.

Genomics-based discovery techniques found no smoking gun in a study of patients with acute exacerbations, stable disease, or acute lung injury, Collard and colleagues reported online in the American Journal of Respiratory and Critical Care Medicine.

Many patients with idiopathic pulmonary fibrosis have periods of stability, interrupted by acute respiratory worsening that can be fatal, the researchers noted. Where the cause is not known, such episodes are called acute exacerbations; occult viral infection has been proposed as a cause since exacerbations are often accompanied by fever, increased cough, and myalgia.

To test the issue, Collard and colleagues used multiplex polymerase chain reaction and a pan-viral microarray discovery platform to test for the presence of known and novel viruses in bronchoalveolar lavage from patients experiencing an acute exacerbation and from controls with stable disease or acute lung injury.

They tested 43 patients with an exacerbation at two centers -- one in the U.S. and one in Japan -- between 2006 and 2009, as well as 40 patients with stable idiopathic pulmonary fibrosis and 29 with acute lung injury.

Twelve of the exacerbation patients had both fever and myalgia, suggesting a viral-like illness, the researchers reported.

Overall, the researchers found evidence of viral infection in 33% of the patients with an exacerbation, only four of whom had evidence of common respiratory viral infections, including two with rhinovirus, one with human coronavirus-OC43, and one with parainfluenza virus-1.